Interesting unit, wonder how much? Honestly, I think my 6500's accuracy is more than adequate for the operating I do. Perhaps I'm missing something? I can't think of any situation where an error of even a few Hz is going to present any problems.

When I got into the hobby in '61 in NJ with a few xtals and an SX85 Hallicarafters receiver, I never really knew where I was. This is simply a 'want' item for me so I never have to think about it again! The panadapter in the Flex is my second 'want'.

Quite possibly, I seem to recall a post saying that some time ago. I've actually got a Flex GPSDO on order (not being able to buy direct from Flex is somewhat irritating for me in UK....Elecraft do it without any problems). For me, the internal fit and integration with 6500 software/firmware makes it worth the £££. Paul M0CVX

During boot the Flex looks at the external 10 MHz input to see if there is a signal. If no signal is present it checks the internal GPS and then the crystal oscillator. This test is only done once. Providing an external 10 MHz reference after the Flex boots will have no effect so you would need to insure that your GPSDO was not only powered up, but locked and providing a stable output before booting up the 6500. The time required for a GPSDO to provide a stable and accurate reference from power-up can be quite lengthy. Unless you leave it powered up continuously that might be an issue.

Unfortunately, Flex only gives you half the possible value of a GPS system -- frequency control. The other half is accurate time. I think I've heard some Flex noises about some day providing NTP service out of the 6500/6700 using the GPS plugin. That would be way cool.

The Jackson Labs device seems to provide a USB interface so could you run NTP on your PC. That's a reason you might choose it.

I would (and did) go with the built-in GPS from FRS because IF (a big capital letters IF) they ever timestamp (TS) I/Q packets the time signal will have to be dead on and I believe the TS will have to be done in the radio and not outside the box by the PC.

Decisions decisions...the external unit can, I believe, provide SNTP when used with GPSCON software http://www.realhamradio.com/gpscon.htm but I haven't fully explored that possibility. Don't know if I need it - doubt it - but it does sound cool!

Since the unit only draws 1/2 w or less, leaving it on all the time for stability would be the way to go.

The external unit seems to me to be more flexible in that it can be used elsewhere when, for example, I upgrade to the Flex 10000 or some other rig in a few years (if I live that long!)

Flex did mention that they might do timestamping in the future. Not really sure what that is myself, and I haven't a clue about whether or not it has to be done local to the rig.

Whether internal or external it should open up the possibility of entering some of the frequency measurement tests.

Ooh err...thanks for this. Made in UK and substantially cheaper than anything else I've seen... Hmmm...worth considering. Okay Flexers, any ideas how this compares in performance to the Flex GPSDO? Is it me, or does the phase noise look high? Grateful for some opinions....Paul M0CVX

The post by Bill, AA7XT, stated in part, "Leo Bodnar GPSDO, is quite a bit less than the Jackson unit and its not a kit." The Jackson Labs LC-XO-Plus GPSDO is assembled and tested by Jackson Labs in the USA. It is available as either an assembled and tested GPSDO or as a kit which includes accessories. The RF connectors on the LC-XO-Plus are MMCX female. The LC-XO-PLUS GPSDO Kit includes 2 each MMCX to BNC-F adapter cables, a 110V to 5V power source, a USB cable and an antenna.

For the record, I own a FLEX GPSDO in my FLEX-6700, a Jackson Labs LC-XO-PLUS GPSDO Kit, and a Leo Bodnar GPS-Locked Frequency Reference. Leo Bodnar does not use the term GPSDO.